AT&T's biggest problem? There are no more new-to-wireless customers out there. Everyone has a cellphone and most people who are going to get data plans already have them. Especially in this economy. There is very little room for growth in this area.

The company reported a net gain of 1.2 million wireless subscribers and 875,000 consumers under contract, up 24.1 percent from the period a year earlier. AT&T also reported 1.6 million iPhone activations in quarter, more than 40 percent of which were for customers new to the company. The company faced declines in its wireline business.

That means 640,000 users switched carriers to AT&T for the iPhone. That is more than half of AT&T's net gain in subscribers and, assuming almost all iPhone users are under two year contract, close to 80% of new contracts were for iPhones. That is assuming AT&T broke even with its other handhelds, which it likely didn't.

The big question for Apple and AT&T is how long can this relationship last? Apple is under intense pressure from iPhone fans that live outside of AT&T coverage (or people that have outstanding issues with AT&T and its service) to let the iPhone work on other carriers. I fall into this group.

AT&T needs the iPhone, but does Apple need AT&T? Cupertino obviously must be getting a pretty sweet deal from the carrier to sign up for multi-year deals that have been reported. Also, Apple likes to keep it simple. Creating an iPhone that worked on Verizon and Sprint would require some new hardware to be built and some more backend wrangling for visual voicemail to work.

AT&T would likely take a big hit on this, which is why they've banned Skype iPhone calls on their network. Why just the iPhone? You can make Skype calls on their laptop data plans or on other AT&T wireless devices, like Windows Mobile and Symbian phones.

The ban is to recoup the high prices that Apple has to charge AT&T to pay for the subsidy that they've put on the iPhone. Most estimates say that AT&T pays for $400 of the iPhone's cost.

What does this all mean? That iPhone customers are likely to be stuck on AT&T for awhile longer. I'm hoping to see a 3G iPod touch in August however.